It's hard for me to understand why more people haven't seen this movie. With the dearth of truly excellent science fiction movies out there, I would think that more people would have been exposed to this very fine, terrifying science fiction thriller. However, if this movie does truly come out on DVD as is rumoured, perhaps more people will get a chance to experience this canonical classic.
This film has every factor you would want in a scary science fiction movie -- a killer robot, artistic statements, a kick-rear-end soundtrack, superior acting, political statements, drugs, the snuffing out of humankind, and even good-old weirdness ("wibbly-wobbly walk"). However, what really sets it apart from the slew of mediocre sci-fi thrillers in this genre is the exceptional screenwriting, which develops the tension, suspense, and terror that grips you so effectively when you watch this movie.
If you like "Alien" and "Aliens", you'll love this movie. In fact, you will love this movie even if you don't like science fiction in general. The only people who shouldn't watch this movie are those who don't like scary movies, because this one will absolutely *terrify* you.